Novel anion receptors for selective recognition of dimethyl phosphinate and carboxylate

Cholesteric Chiral Molecular Tweezer for Rapid Detection of F- in Food Samples

Chiral cholesteric molecular tweezer 7d was synthesized and its influences on changes in the ultraviolet (UV) and fluorescence spectra of various anions were investigated. The results displayed that molecular tweezer 7d selectively recognized F⁻ ions in dimethyl sulfoxide with a detection limit of 5.14 μmol/L, while other anions had little interference. On this basis, a method for the rapid detection of F⁻ ions by host molecular tweezer 7d was established, and the naked-eye detection of F⁻ was realized through the unique yellow color of the complex solution. According to the determination of F⁻ ions in real food samples, it was proved that the established method had good application prospects in F⁻ ion detection.

Macrocyclic versus open-chain carbazole receptors for carboxylate binding

Anion recognition properties of six synthetic acyclic and macrocyclic carbazole-based receptors have been studied by 1H-NMR as well as with COSMO-RS calculations towards acetate, benzoate, lactate, sorbate and formate. The...

Synthesis of new chromogenic sensors containing thiourea and selective detection for F–, H2PO4–, and Ac– anions

Two new chromogenic sensors 1-(2-hydroxyphenyl)-3-(4-nitrophenyl)thiourea 1 and 1-(3-hydroxypyridin-2-yl)-3-(4-nitrophenyl)thiourea 2 bearing nitrophenyl and thiourea groups were designed and synthesized by one-step procedure and characterized through 1H NMR, 13C NMR, FTIR, and MS. The anion recognition property of the receptors was studied via naked-eye detection, UV–vis, and 1H NMR. Based on the existence of amino gen and hydroxyl moieties in receptors, receptors 1 and 2 exhibit obvious selectivity by the redshift of UV–vis signals, colour changes through naked-eye detection, and binding effects for F–, H2PO4–, and Ac–. Surprisingly, the detection limits of receptor 1 for F– and Ac– were calculated to be 5.45 × 10−7 and 2.11 × 10−7 (mol/L)−1, respectively, which indicated that F– and Ac– can be identified with high sensitivity by receptor 1. Besides, simple “test strips” were developed and were used as sensors for recognition of F–, H2PO4–, or Ac– in DMSO solution. Lastly, the mechanisms of the recognition process were studied through DFT calculation and 1H NMR titration.

Agonist-mediated switching of ion selectivity in TPC2 differentially promotes lysosomal function

Ion selectivity is a defining feature of a given ion channel and is considered immutable. Here we show that ion selectivity of the lysosomal ion channel TPC2, which is hotly debated (Calcraft et al., 2009; Guo et al., 2017; Jha et al., 2014; Ruas et al., 2015; Wang et al., 2012), depends on the activating ligand. A high-throughput screen identified two structurally distinct TPC2 agonists. One of these evoked robust Ca²⁺-signals and non-selective cation currents, the other weaker Ca²⁺-signals and Na⁺-selective currents. These properties were mirrored by the Ca²⁺-mobilizing messenger, NAADP and the phosphoinositide, PI(3,5)P₂, respectively. Agonist action was differentially inhibited by mutation of a single TPC2 residue and coupled to opposing changes in lysosomal pH and exocytosis. Our findings resolve conflicting reports on the permeability and gating properties of TPC2 and they establish a new paradigm whereby a single ion channel mediates distinct, functionally-relevant ionic signatures on demand.